Bad Connection

I am not happy with this setvice provider, i have been using rain for about 3 months now, first 2-3 weeks was getting decent line speed of 10/11mbps which is enough for me at this stage, ever since then i get around 1.5-2mbps,cant even load a webpage. Phoned numerous times, have been told couple times my fault has been logged and situation will be looked at and ill be cintacted and suprise that never happened. Why must one pay for something that you cant even use at all!!!!